1. Field of the Invention
The present invention relates to a data bus system, and more particularly to a data bus having only a single bus having extra signal lines that are used to compensate for faulty, malfunctioning signal lines.
2. Description of the Related Art
In a data bus system using a single data bus having a plurality of signal lines, when one or more signal lines among the plurality of signal lines malfunction, the data bus ordinarily cannot function properly.
U.S. Patent Application No. 2002/0099980 A1 to Olarig seeks to overcome such a problem when a 64 bit bus is being used. In Olarig '980, the 64 bit bus is composed of a 32 bit upper bus and a 32 bit lower bus. If there are no malfunctioning signal lines, the entire 64 bit bus is used to transmit data. If at least one signal line on the upper 32 bit bus has a parity error, data is then transmitted only via the lower 32 bit bus. If at least one signal line on the lower 32 bit bus has a parity error, data is then transmitted only via the upper 32 bit bus.
However, a major drawback of the Olarig '980 system is that if there is a single faulty signal line in both of the upper and the lower 32 bit busses that make up the 64 bit bus, the entire 64 bit bus cannot be used to transmit data. Thus, by just having two erroneous signal lines on the 64 bit bus of Olarig '980 can render the entire 64 bit bus in Olarig '980 unusable. This is inefficient. Another drawback of the Olarig '980 system is that a single faulty signal line in Olarig '980 disables 32 signal lines, forcing data to be transmitted on a 32 bit bus instead of a 64 bit bus. This too is inefficient.
I have not seen a data bus method or apparatus that disables only individual faulty signal lines and substitutes extra supplemental signal lines for the faulty signal lines to enable data transmission on a data bus having one or more faulty signal lines. Therefore, what is needed is a more efficient data bus arrangement that can efficiently compensate for faulty signal lines without consuming enormous resources.